Penn scientists used an MRI innovation, called "arterial spin labeling," to image blood flow in the brain and match patterns of flow with cognitive decline. In a study published last week in Neurology, experts read the new type of MRI and PET scans of Alzheimer's patients and healthy people. Both technologies enabled them to reliably identify the patients.
MRI is preferable to PET for several reasons, said John A. Detre, a professor of neurology and radiology who was senior author of the study.
For one thing, MRI is more widely available.
For another, PET requires a radioactive tracer. This makes PET about twice as expensive as MRI, and the radiation exposure, while low, means patients can't have repeated PET scans to track brain changes.
Since MRI is already part of the diagnostic workup for Alzheimer's, incorporating the new application would simply add 10 minutes to the standard scan - and avoid the need for PET.
Why improve diagnosis of a disorder for which there is no therapy to stop or reverse the damage? A big reason is so that researchers can actually discover such a therapy. Currently, drug development is hampered by the inability to identify patients in early stages and then measure whether their brains respond to a compound.
Among those who "are most excited about this kind of imaging are drug companies trying to develop treatments," Detre said.
- Marie McCullough
